The invention relates in general to diesel motors and in particular to a new and useful device for controlling a diesel motor driven pump drive with injection pump and feed pump, a feed line leading from the feed pump to a load and a pressure resistance behind the load, and, if necessary, a return line leading back to the sump of the feed pump.
According to the principle of energy conservation, each compound system must give off an amount of energy corresponding to the energy input. If the power input is greater than the power output, the balance is converted to thermal power. In a pump drive comprising an injection pump, diesel motor and feed pump, the residual energy to be converted to thermal power appears when excess flow medium under pressure is conducted over a resistance, e.g. a pressure resistance, and is expanded. The heat released in this process is lost to the atmosphere. If the load power is zero, the entire feed pump power is converted to thermal power and is released into the atmosphere as liberated heat. This results in excess energy expenditure, consumption of flow medium, and wear on the pressure resistance. If the thermal power is to be zero, which is the principal goal, the power input of the feed pump must be equal to the required and actual load output.